×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Max Flow through pipe

Max Flow through pipe

Max Flow through pipe

(OP)
I am confused about flow concept and would appreciate your help.

I have a 2" pipe going to a tank from another 10" line. The pressure at the tie in point is 5 barg. Whats the max amount of water that will flow through pipe  

RE: Max Flow through pipe

Flow rate is a function of dP, pipe size, pipe length, and pipe roughness.  You didn't say what pipe material or how long the 2-inch was.  If it is less than a meter long and some really slick pipe then the flow rate is pretty high.  If it is 2 miles of old, scaly cast iron then the flow rate is noticeably less.

David

RE: Max Flow through pipe

you don't give much information.  Aside from pressure drop, pipe size, length, and surface roughness, it's also an issue of configuration off the 2" off of the 10".  A branch off the T (probably what you have), will have more pressure drop, and so usually less flow, but driven also by the pressure in the 10".

If one is to design a system for flow, optimal velocity is around 7 ft/sec, or 2.1 m/s.  That would mean around 75 gpm.  You would be hard pressed to get more than about 100 gpm in the 2 inch line, and virtually assured to be at least 50 gpm.

RE: Max Flow through pipe

As explained in earlier post by zdas and cheute, the water flow is function of several factor.

The concept is: the pressure drop (depends on flowrate) of water flowing in the pipe will be equal to available delta pressure in the system. The calculation to calculate the pipe system capacity itself is an iterative effort.

For example:
your tie-in point pressure : 5 barg
your tank pressure (at the point the water enter): 2 barg
your available delta pressure : 3 bar

You then develop your pipe model, incorporate all the length, fitting, valve, pipe type (roughness), pipe size etc. Then start the iterative process by trial and error input the flowrate and calculate the pressure drop. The flow that give you pressure drop equal to 3 bar then is the capacity of your pipe system.

The capacity of your pipe system can be change if your pipe condition change (change in pipe roughness), your tank pressure change (change in available delta pressure) etc...

hope this help

-rayz-

RE: Max Flow through pipe

David, you state "Flow rate is a function of dP, pipe size, pipe length, and pipe roughness." is there one calcualtion that ties all these factors in ? eg can I calculate dp if I know the other variables ?

RE: Max Flow through pipe

Yes you can figure it out if you know dp. go to RC-6 and you will find that equation wich will help you to find other factor.

http://www.psig.org/papers/2000/0112.pdf

this might help u.

RE: Max Flow through pipe

RC-6?

Good luck,
Latexman

RE: Max Flow through pipe

Alberto:

I would do as devaxrayz put it, with further addition. I think you need to analyze this problem abit more than the simplistic form of looking at max flow. You need pipe characteristics,i.e material of pipe, roughness, length to point of delivery, types of bends if any to delivery point, types and number of valves (orofices, venturi etc as these have different delta-P's in addition to the pipe length delta p) and lastly wether the point of delivery is at the same elevation or not from supply). So max flow of water- going where? can be answered fully with your analysis of complete flow diagram.  

RE: Max Flow through pipe

I sincerely hope Alberto gets the help that he needs.  Forgive me for being suspicious but the problem statement reminds me of some of my old fluid mechanics homework assignments (from what I can recall 15 years ago).

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources